Treatment of rheumatoid arthritis patients with anti-TNF-alpha monoclonal antibody is accompanied by down-regulation of the activating Fcgamma receptor I on monocytes.

Objectives To study the effect of anti-TNF-α therapy on activating IgG Fc receptor (Fc α therapy on activating IgG Fc receptor (Fc α γ therapy on activating IgG Fc receptor (Fcγ therapy on activating IgG Fc receptor (Fc R) expression on monocytes of RA patients in γR) expression on monocytes of RA patients in γ relation to changes in disease activity. Methods RA patients were treated with anti-TNF-α mAb (infl iximab). At baseline, 2 and 14 weeks after the start of anti-TNFα mAb (infl iximab). At baseline, 2 and 14 weeks after the start of anti-TNFα α treatment, FcγR expression levels on circulating monocytes were evaluated. Changes in expression were correlated to γR expression levels on circulating monocytes were evaluated. Changes in expression were correlated to γ changes in disease parameters. To study the direct effects of TNF-α blockade on monocytic Fc α blockade on monocytic Fc α γ blockade on monocytic Fcγ blockade on monocytic Fc R expression levels, γR expression levels, γ monocytes were isolated and cultured with anti-TNF-α mAb. The effects were compared with those induced by TNFα mAb. The effects were compared with those induced by TNFα α.